VAX 780 on eBay

Grant Taylor cctalk at
Sat Jan 1 13:38:46 CST 2022

On 1/1/22 12:33 PM, Paul Koning via cctalk wrote:
> And mainframes may use 3-phase power supplies; CDC 6000 mainframes do, 
> though with those it's 3 phase 400 Hz produced by motor-generators 
> (which in turn run off 3-phase mains power).

I know that some IBM mainframes prefer 3ɸ power but I know of multiple 
people that have re-wired their CECs to use 1ɸ power.  They too are 
largely independent 1ɸ supplies on different phases to jointly power a 
common internal bus.  So re-wiring the necessary supplies to the same 
phase is mostly not a big deal.

Apparently even IBM sold and supported some systems in this 
configuration.  The only down side is that it put an upper cap on the 
amount of power that you could draw and thus things that you could run 
in this configuration.  But for smaller installations, it's perfectly fine.

Grant. . . .
unix || die

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